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1. I used SketchUp. 2. I do not. But it is a lot of parts. I mention the highlights in the post at https://diysolarforum.com/threads/cargo-trailer-solar-panel-roof-rack-design-review.18084/post-339118 FYI - I'm rarely on this site any more. It's only blind luck that I saw your reply so soon.

As mentioned in post #3, I couldn't because my interior and ceiling were done by the time I got around to working on the roof rack.

In the end I gave up on using rivnuts for my setup. I ended up drilling and tapping holes through the roof into the steel frame tubing. Lots of bolts, VHB tape, Butyl tape, and lap sealant. 18 months later and over 12k miles of towing and the rack is doing great. See...

There is a difference between general terms and specific units. I = current A = amps (one specific unit of current) E = voltage V = volts (one specific unit of voltage) My original post was referring to the common units, not the general terms.

You are assuming a 14.4V battery. I assumed a 26V battery based on info in post #4.

See the following document. It shows resistor sizes for a given voltage. The wattage of the inverter is irrelevant for choosing the resistor. https://diysolarforum.com/resources/inverter-disconnect-switch-with-precharge.60/

Look at the spec sheet for the Victron SCC. It will show a value for "Max. PV short circuit current". Keep your array Isc under that value. Exceeding it can damage the controller. Also note that, like Voc, the Isc of a panel changes a bit with temperature. But it's the opposite. Isc goes up...

Since the breaker's only purpose will be to act as a disconnect and not for any kind of protection of the wires you can use any breaker size over the Isc of 22.28A. I'd choose either the 40A or 63A. Then if you add a 3rd parallel string at some point you won't need to change your disconnect...

I would use STC specs when working out whether a solar panel array can be used with a specific SCC. Just remember that Voc changes with temperature so account for that. I would use NOCT to get a better idea of what you might really get for planning purposes.

The length and size of the wire helps calculate voltage drop. Definitely worry about that when you are getting ready to buy the wire but I wouldn't worry about that when deciding which SCC to buy. Something to consider though. You seem to be buying one piece of equipment at a time and then...

Yep. Very simple. Just respect that you will be dealing with about 120VDC. Series has a lot of benefits. Simpler install. No fuses needed. Lower amperage means smaller, cheaper wire. Better lower light performance. Just make sure all three panels in series are in the same plane and you don't...

Solar panels don't push power to the SCC. The SCC only draws the power it needs, up to the the max that the panels are capable of producing at the moment. The VictronConnect app is showing you how much the controller is using from the panels. When the battery is full and there are no loads then...

Use Victron's MPPT calculator. You can enter the specifics of your panels and play around with different layouts and it will recommend the best matching charge controller. The 150/35 would be a great choice for your panels in series. https://www.victronenergy.com/mppt-calculator

You need as much battery as you need for your energy usage. Do a full energy audit so you know how much you need. Don't forget to include the idle power consumption of your Growatt. https://diysolarforum.com/resources/system-energy-audit-and-sizing-spread-sheet.12/

There is more than one way to wire together two (or more) batteries in parallel. With just two batteries where the two batteries are directly wired together in parallel there is no need to worry about any wire lengths at all. The only requirement is that the two wires going to "the system" from...

Why only 67%? I see no problem using 80% regularly, 90% on occasion. I suggest doing a full energy audit so you know for sure what you need. Also keep in mind that with a van you can charge while driving. https://diysolarforum.com/resources/system-energy-audit-and-sizing-spread-sheet.12/

Assuming the 50A SCC is an MPPT then you can easily put your 4 panels in 2S2P or possibly even 4S (depending on the actual panel Voc and the SCC's max PV input voltage). The fact that you have a 12V battery is irrelevant in that decision.

Are the 4 panels on the roof wired as 4P, 2S2P, or 4S? The only way you can wire the 5th panel (as a ground mount) into the same 50A SCC used by the 4 roof panels is if the 4 roof panels are wired in 4P. And 5 panels in parallel will require some big wire and all 5 need to be fused. Having the...

Not for the wires connecting each battery to the battery bus bars. Since each battery is not carrying the full 320A charge current you can use smaller wires. Pick a max charge current you want to support. 0.5C is 140A and 1C is 280A. I would try to keep each battery's charge current on the...

You have 4 48V batteries. They have to be in parallel. If you connect the 4 batteries in series you will have a 192V system. The battery and bus bar arrangement I described in post #16 puts the batteries in parallel.

Are you talking about gluing flexible solar panels or rigid solar panels to the van roof? I strongly urge you to avoid using any adhesive for solar panels. Keep in mind that flexible solar panels don't last long. You will probably need to replace them every couple of years. That will be a...

For 320A of charge current you definitely need 4/0AWG. 0.5C on a 280Ah battery is 140A and 1C would be 280A. That's per battery in parallel. So 4 in parallel can handle 4 x 140A = 560A at 0.5C. So you will have no issue with 320A. Even 3 in parallel can handle more than 320A.

That chart gives you a rough calculation. In your case you would want the 1.1 number for 32ºF (you said that's the coldest it gets, right?). 150V / 1.1 = 136.4V so that's close to what I came up with. It's an aiming point to help narrow down your search. Once you have a specific panel in mind...

With a 2400W inverter on a 24V system you only need about 110A of discharge current. Another important issue is the max charge current. You have a 100A charge controller. Make sure the chosen set of batteries can handle 100A of charge current (in addition to the 110A of discharge current). The...

With 4 big batteries like that I think it makes sense to have two sets of bus bars. Wire the 4 batteries in parallel to the first pair (battery bus bars). Wire the all-in-one and two charge controllers to the other pair (system bus bars). Then run a big wire with the 400A Class T fuse between...

Both questions are dependent on the exact same set of details and you must be sure your bus bars are rated higher than the max fuse size you end up with. Now that we know you need a 400A battery fuse this means you want 450A or 500A bus bars. You do not want bus bars that are weaker than the...

OK. You effectively have 1 inverter and 3 charge controllers. That's a 3000W inverter and (120A + 120A + 80A) 320A of charge controllers. Then you need a 400A Class T fuse at the battery, and a 150A non Class T fuse at each of the two SC48120.

Your other question is tightly related to this one: https://diysolarforum.com/threads/does-adding-extra-charge-controllers-increase-the-size-of-busbar-needed.44316/

Your other question and this one are tightly related. They really should be discussed as one. https://diysolarforum.com/threads/blue-sea-class-t-vdc.44317/

You're 50% over paneled with 18kW on a system that can only support 12kW. Do your batteries each support 60A of continuous charge current?

You have two 48V 3000W all-in-ones, correct? So the inverters can pull 6000W / 48V / 85% = 150A from the batteries. If the charge controllers are 120A each then that's 240A possible going into the batteries. Since 240A is bigger than 150A (obviously) then fuse based on 240A. 240A x 125% = 300A...

The Class T should be between the battery and bus bar, close to the battery. Having it near the inverter doesn't really help much.

Where is this Class T fuse meant to go? Normally you only need a Class T fuse as the main battery fuse between your batteries and the main bus bars. It would be sized for the max total current draw being pulled from the batteries or for the max total charge current going to the batteries, which...

Yeah, ultimately you need the total circuit path to be the same length for each battery. Seems simpler to have the positive leads the same as each other and the negative leads the same as each other but if your setup prefers a different approach that still results in equal total path lengths...

For only two batteries: C. Connect the two battery positives. Connect the two battery negatives. Connect positive of one battery to breaker to Growatt. Connect negative of other battery to Growatt (with possible shunt in between). This is the "diagonal" method shown the Unlimited Wiring...